Dometic 3 flashes fault code — Furnace
Applies to: DFSA/DFSD/DFMD/DFLD/DFLA furnace series
What 3 flashes means
The Dometic DF furnace manual lists 3 flashes with a 3-second pause as an ignition lockout fault.
Owner-safe checks
- Turn the thermostat off.
- Do not keep cycling the furnace if ignition lockout returns.
Service-only work
- Ignition, gas, burner, board, and combustion diagnosis is qualified RV furnace service work.
Safety boundary
RV furnaces burn LP gas and can create fire, explosion, electrical, burn, and carbon monoxide hazards. Shut the furnace off and do not service burner, board, wiring, gas, or combustion parts unless qualified.